Convertible sofa



FIG. 1 is a front perspective view of a convertible sofa showing my design in position for use as a sofa;

FIG. 2 is a rear perspective view;

FIG. 3 is a end elevational view; and

FIG. 4 is a perspective view showing the sofa in its converted position for use as a bed. 

The ornamental design for a convertible sofa, as shown and described. 